CMD_READ

read sectors of data from a disk.

This command reads data from the drive to a supplied buffer.

io_Device

preset by the call to OpenDevice()

io_Unit

preset by the call to OpenDevice()

io_Command

CMD_READ

io_Flags

0 or IOF_QUICK

io_Data

pointer to the buffer where the data should be put

io_Length

number of bytes to read, must be a multiple of the drive block size.

io_Offset

byte offset from the start of the disk describing where to read data from, must be a multiple of the drive block size.

io_Error

0 for success, or an error code as defined in <devices/trackdisk.h>

This command can only reach data below the 4GB barrier. To read data beyond the barrier, use TD_READ64 instead.

Some incarnations of the scsi.device, namely those that handle actually IDE devices, were unable to read more than 255 blocks in one go. This bug has been fixed in V47.

CMD_WRITE, TD_READ64